Following an email from Grey a while ago I went searching for an article by richard marsh (Audio Magazine) from the seventies. I believe this is it:

Thanks for the tip Grey I got a lot out of reading this article (I will never consider ceramics for by-passing, or anything else audio related, again). I believe others on the forum will to.

Aye, that's the one. I still remember when I got that issue of Audio (I had a subscription back then)--it was a shocker, because I had always heard that passive components *weren't* audible. (This was back when I still thought distortion specs counted for something, too, which goes to show you that I still had a lot to learn...) Later, I discovered that folks who *listened* to stereos had been saying so for a while, but I had never heard of any such thing.
A tip of the hat to Richard Marsh, (I believe Jung was involved somewhere in the process, too) for laying it out so clearly. I know it's sure made a difference in my system over the years. Coincidentally, I'm about to try a bank of Solen (metallized polypropylene) caps on each of the Aleph 2s I built. I'll be curious as to how much difference they make in detail retrieval, as that's one area where my tube amps still outperform the Alephs. So far, except as noted elsewhere--the input network, and omission of C6 (I think that's the right one)--I've been using the Alephs stock; as laid out in the service manuals. My tube amps have scads of film caps (Solen & MIT), so I decided that I'd level the playing field; give Nelson's circuit a chance at some of the good stuff.